TIMBER LOSSES CAUSED BY TERMITES, DECAY AND FIRE IN AN ALPINE FOREST IN NEW SOUTH WALES

Abstract

A rating system for the assessment of damage to forest trees by termites, decay and fire is described. Timber and royalty losses were assessed during harvest cuts of alpine ash (E. delegatensis R. T. Baker) and mountain gum (E. dalrympleana Maiden) in seven compartments in Bago State Forest, New South Wales. In one compartment, part of which was a virgin stand of alpine ash, the combined losses due to these agencies were assessed at £37/13/- per acre, of which £1/15/- was due to downgrading merchantable logs, £23/12/- due to rejection of logs because of defect and £12/6/- per acre due to losses in trees which were ringbarked because of excessive defect. The total royalty return in this compartment was £71 per acre. These trees were from 60 to 150 years old when cut. In a compartment previously treated by logging and ring-barking, and protected from fire from 1917 onwards, the losses were £6/5/- per acre, of which £5 per acre was contained in overmature seed trees. The royalty return in this compartment was £34 per acre from trees, 90 per cent of which were less than 70 years old when cut. The losses were due mainly to termites Porotermes adamsoni (Froggatt) which caused up to 80 per cent of the damage, and to decay which caused 13 to 36 per cent. The actual loss due to damage by fire was less than 5 per cent of all losses; but fire was the cause of most scars, through which fungi and termites gained entry. Between 80 and 91 per cent of the loss in each compartment was contained in large trees 90–150 years old.